Original application discloses a seesaw button of the control means 5 for opening or closing the umbrella. However, there is not provided with any safety device for preventing a false depression of the lower button portion 513 of the seesaw button, whereby when depressing the upper button portion 512 of the seesaw button for opening the umbrella and when the umbrella is not yet fully opened, a further depression of the lower button portion 513 will suddenly close the umbrella and release the spring energy of the opening spring 3 to possibly eject the central shaft means 1 to cause unexpected accidental injury to a user or nearby person. Meanwhile, the long drag rope 56 is flexible, windable and foldable within the telescopic tubes of the central shaft means 1 and will be easily tangled in the hollow central shaft means, thereby influencing a smooth operation of the umbrella.